Intraocular pressure detecting device and detecting method thereof

ABSTRACT

An intraocular pressure detecting device includes an image capturing unit, a processor, and a pressure detection unit. The image capturing unit, coupled to the image capturing unit, is capable of acquiring an eye image. According to the eye image, the processor can determine an intraocular pressure detection area. After the pressure detection unit detects the intraocular pressure detection area, the intraocular pressure is calculated by the processor of the intraocular pressure detecting device.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to an intraocular pressuredetecting device. Particularly, the present invention relates to anintraocular pressure detecting device capable of determining anintraocular pressure detection area.

2. Description of the Prior Art

The conventional intraocular pressure detecting device for testing andcontrolling eye fluid pressure includes a surgical apparatus forpenetrating into eyeballs. A fluid pressure convertor is installed onthe surgical apparatus, such that when the surgical apparatus penetratesthe eye, the fluid pressure convertor is positioned near the opening.Since the opening communicates with the interior of the eye, the fluidpressure convertor is able to react to the change in fluid pressurewithin the eye and correspondingly generate a signal to reflect suchchange in fluid pressure. In other words, conventional intraocularpressure measuring devices are devices invasive to the eye and aregenerally unwelcomed by the general public.

Recent generations of intraocular pressure detecting devices includenon-invasive devices that are slowly displacing the conventionalinvasive intraocular pressure detecting devices. Non-invasiveintraocular pressure detecting devices can be classified as contact ornon-contact forms. In either forms, an external force is exerted on thecornea in order to extrapolate an intraocular pressure measurement fromthe relationship between the external force and the deformation of thecornea. However, research has shown that the curvature as well as thethickness of the cornea provides a certain margin of error in the actualintraocular pressure readings. Therefore, it is of major significance tothe current industry to research and develop intraocular pressuredetecting devices capable of determining appropriate intraocularpressure detection areas.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an intraocularpressure detecting device and an intraocular pressuring detecting methodthereof, capable of determining appropriate intraocular pressuredetection areas.

The intraocular pressure detecting device includes an image capturingunit, a processor unit, and a pressure detection unit. The imagecapturing unit is used for capturing an eye image. The processor unit iselectrically coupled to the image capturing unit and determines anintraocular pressure detection area in accordance to the eye image.After determining the intraocular pressure detection area, the pressuredetection unit detects the intraocular pressure detection area andcorrespondingly generates a pressure detection signal, wherein theprocessor unit determines an intraocular pressure according to thepressure detection signal.

The intraocular pressure detecting method includes the steps ofcapturing the eye image, analyzing the eye image and determining theintraocular pressure detection area, measuring the intraocular pressureof the intraocular pressure detection area and correspondinglygenerating the pressure detection signal, analyzing and comparing thepressure detection signal, and determining the intraocular pressure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of an embodiment of the intraocularpressure detecting device;

FIG. 2 is an embodiment of the image capturing unit capturing the eyeimage;

FIG. 3 is an embodiment of the processor unit determining theintraocular pressure detection area;

FIG. 4 is an embodiment of the pressure detection unit measuring theintraocular pressure detection area of the eye;

FIG. 5 is another embodiment of the pressure detection unit measuringthe intraocular pressure detection area of the eye;

FIG. 6 is a top view of another embodiment of the elastic member of thepressure detection unit;

FIG. 7 is a top view of yet another embodiment of the elastic member;

FIG. 8 is a diagram of an embodiment of the third electrode raising thesignal-to-noise ratio;

FIG. 9 is a diagram of an embodiment of the vibrations directly detectedin the intraocular pressure detection area by a reference electrode ofthe elastic member;

FIG. 10 is a flow chart diagram of an embodiment of the intraocularpressure detecting method.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIG. 1, an intraocular pressure detecting device 10includes an image capturing unit 20, a processor unit 30, and a pressuredetection unit 40. As shown in FIGS. 1 and 2, the image capturing unit20 may be used to capture images of an eye 50. In the presentembodiment, the image capturing unit 20 may be a photographic device201. Specifically, the photographic device 201 may be a CCD (ChargeCoupled Device) photographic camera or a CMOS (Complementary Metal OxideSemiconductor) photographic camera, wherein the photographic device maybe focused with wide-angle reflection mirrors in order to capture apanoramic image of the eye 50. Since intraocular pressure may not bedetermined from surfaces other than the surface of the eye, such aswounds and other areas where intraocular pressure may be difficult tomeasure, the image of the eye 50 captured by the photographic device 201may be selected from a cornea image, an eyelid image, an eyebrow image,and an orbit image to provide position for the overall eye and forselecting an intraocular pressure detection area 303 (as shown in FIG.3).

The image capturing unit 20 may also be a photoelastic stress analyzer,providing stress distribution of the corneal area. Projected light fromthe photoelastic stress analyzer is composed of two light components: alight component parallel to the force an eye experiences (ex.intraocular pressure) and a light component perpendicular to the sameforce. Since the speed of light is proportional to the pressure, theprojected light (and thus the two components) will travel through theeye at different speeds according to different pressures, resulting inphase shift. If the phase shift is constructive, the two components willbe additive and form a bright area. However, if the phase shift causesthe two components to be mutually disruptive, a dark area will beformed. In this manner, the lines formed by the bright and dark areas onthe eye may be observed and analyzed by the photoelastic stress analyzerto calculate and explain the pressure gradient distribution of cornea,as shown in FIG. 3. In addition, the pressure gradient distribution ofcornea facilitates the selection of the intraocular pressure detectionarea 303 in order to further carry out the intraocular pressuremeasurement.

As shown in FIGS. 1 and 2, whether the image capturing unit 20 is thephotographic device 201 or the photoelastic stress analyzer, when theintraocular pressure detecting device 10 of the present inventiondetermines a need to track a specific area of the eye 50, the field ofview of the panoramic image captured by the image capturing unit 20 maybe adjusted by the intraocular pressure detecting device 10. When theimage capturing unit 20 detects the mentioned specific area of the eye50, the intraocular pressure detecting device 10 may be utilized torotate or shift to move the position of the focal point, such as movingthe focal point from the eyelid to the cornea or any other positions onthe eye 50, such that the function of dynamic tracking of the eye 50 maybe achieved. Furthermore, in other embodiments, the image capturing unit20 may also adjust the resolution of the panoramic image view of the eye50 by way of the electrical coupling with an optical focusing unit (notshown).

As shown in FIG. 1, the processor unit 30 is electrically coupled to theimage capturing unit 20 (e.g. photographic device 201 or intraocularpressure analyzer), wherein the processor unit 30 includes ananalog-to-digital convertor 301 and a microprocessor 302. The image ofthe eye 50 and the eye image signal is transmitted to and processed inthe analog-to-digital convertor 301 to generate an eye image electricalsignal. The microprocessor 302 analyzes the eye image electrical signalto find preferable detection areas of the pressure gradient distributionin order to determine a suitable intraocular pressure detection area303, as shown in FIG. 3. Simply, the processor unit 30 determines theintraocular pressure detection area 303 according to the image of theeye 50 and the eye image signal.

Since the curvature and thickness of the cornea produces a bias in theactual value of the measured intraocular pressure, the determination ofthe intraocular pressure detection area is, in practice, very importantto the measurement of the intraocular pressure. As shown in FIGS. 1, 3,and 4, in order to precisely measure the actual intraocular pressure, apressure detection unit 40 proceeds with intraocular pressure testing onthe intraocular test area 303 after the intraocular test area 303 hasbeen determined.

As shown in FIG. 4, the pressure detection unit 40 is an elastic member401. Elastic member 401 includes a first electrode 402 and a secondelectrode 403. Since the elastic member 401 is formed from dielectricmaterials, the first electrode 402 and the second electrode 403 may forma capacitive sensor device. In other words, the pressure detection unit40, in the present embodiment, conducts intraocular pressuremeasurements through the capacitive sensor device by direct contact. Asshown in FIG. 4, the first electrode 402 and the second electrode 403 ofthe pressure detection unit 40 are respectively disposed on a topsurface 4011 and a bottom surface 4012 of the elastic member 401. As theelastic member 401 comes in contact with the eye 50, the elastic member401 will deform, which leads to a difference in the space h between thefirst electrode 402 and the second electrode 403. This difference in thespace h may be used to measure dynamic changes in the intraocularpressure. In the present embodiment, the first electrode 402 and thesecond electrode 403 are arranged symmetrically. However, in otherembodiments such as shown in FIG. 5, the first electrode 402 and thesecond electrode 403′ of the elastic member 401′ may be arrangedasymmetrically. The symmetric or asymmetric arrangement mentioned aboverefers to whether or not the first electrode 402 on the top surface 4011of the elastic member 401 or 401′ are symmetrically arranged in thevertical direction with the second electrode 403 or 403′ on the bottomsurface. Specifically, the vertical directions of the first electrode402 and the second electrode 403 or 403′ are parallel with the spacing hbetween the first electrode 402 and the second electrode 403.

The embodiment shown in FIG. 6 illustrates a top view of an elasticmember 401″. The first electrode 402′ and the second electrode 403″ maybe arranged on the elastic member 401″ as rings on the same plane. Asseen in the top view diagram of an embodiment of an elastic member401′″, in order to strengthen the effects of the capacitive change, aplurality of electrodes 80 may be arranged as rectangles that areadjacent to each other such that the capacitive sensing area between theelectrodes 80 is in practice much bigger. In addition to being able tomeasure the dynamic changes to the intraocular pressures, the elasticmembers 401″ and 401″ with the large surface areas of FIGS. 6 and 7 mayalso utilize the capacitive sensing between the wide area rangedelectrodes to measure the curvature of the intraocular pressuredetection area 303. Therefore, the elastic members 401″ and 401′″, inaddition to being able to measure the dynamic changes to intraocularpressures, they can also measure the curvature of the cornea such thatthe bias in the measurement of the intraocular pressure due to thecurvature of the cornea or cornea thickness within the intraocularpressure detection area 303 may be reduced.

Usually, the inner pressures within the eye, or more commonly known asthe intraocular pressure, will cause high frequency vibrations of thecornea. These vibrations will cause the space h between the electrodesto change and result in the transmission of signal. As shown in FIG. 8,dynamic changes (such as high frequency vibrations) to the intraocularpressure may be deduced from the changes in the space h between thefirst electrode 402 and the second electrode 403 due to the deformationof the elastic member 401. Specifically, the changes to the space hbetween the first electrode 402 and the second electrode 403 willgenerate a pressure detection signal 60, wherein the processor unit 30will then determine an intraocular pressure according to the pressuredetection signal 60. As shown in FIGS. 1 and 8, the pressure detectionsignal 60 measured by the pressure detection unit 40 will be transmittedback to the processor unit 30. Once the analog-to-digital converter ofthe processor unit 30 processes the pressure detection signal 60, thesignal is then transmitted to the micro-processor 302. Themicro-processor 302 compares the processed pressure detection signal 60to the corresponding intraocular pressure and determines the intraocularpressure of the eye 50.

As shown in FIG. 8, in order to further decrease signal noise, theelastic member 401 further includes a third electrode 404, wherein thethird electrode 404 is disposed between the first electrode 402 and thesecond electrode 403. Since the third electrode 404 is disposed betweenthe first electrode 402 and the second electrode 403, when the space hbetween the first electrode 402 and the second electrode 403 changes,the third electrode 404 is able to provide signals pertaining to thespace between the first electrode 402 and the third electrode 404, aswell as the space between the second electrode 403 and the thirdelectrode 404. In this manner, signal noise may be decreased while theaccuracy of the pressure detection signal between the first electrode402 and the second electrode 403 is increased, raising thesignal-to-noise ratio as a result. The signal-to-noise ratio referred toherein is defined by the ratio of the signal divided by the signalnoise.

As shown in FIG. 9, the elastic member 401 further includes a referenceelectrode 405, wherein the reference electrode 405 can directly detectvibrations of the intraocular pressure detection area 303. Thevibrations may be compared to a default database, wherein the vibrationsmay be classified as low frequency vibrations from eye movements or ashigh frequency vibrations from intraocular pressures such that, inpractice, misjudgment cases may be reduced.

The above mentioned embodiments deal with the elastic member 401proceeding with the detection through direct contact methods. However,the image capturing unit 20 may also capture the eye image to producethe eye image signal through non-contact methods. The eye image (andsubsequently the eye image signal) includes a cornea image, an eyelidimage, an eyebrow image, and an orbit image. The eye image 50 and theeye image signal are transmitted to the analog-to-digital converter 301of the processor unit 30 to generate the eye image electrical signal.The micro-processor 302 compares and analyzes the eye image electricalsignal to find preferable detection areas of the pressure gradientdistribution in order to determine a suitable pressure detection area303. The image capturing unit 20 can detect tomography graphs of thepressure detection area 303 and then utilize changes in the time domainpattern matching analysis to obtain the pressure detection signalresulting from the intraocular pressure. Specifically, the imagecapturing unit 20 may simultaneously provide functions of the pressuredetection unit 40. The image capturing unit 20 is not limited to theembodiment shown in FIG. 2, as it can also be other optical imagecapturing units that can receive optical signals. In practice, the imagecapturing unit 20 utilizes principles of optical interference to capturethe eye image signal. These eye image signals include the mentionedcornea thickness data, corneal section image data, and corneal curvaturedata. After the mentioned data are transmitted to the micro-processor302, in addition to being able to determine the intraocular pressuredetection area, the micro-processor 302 may also correct theinterpretation of the intraocular pressure. During the intraocularpressure detection procedures, the image capturing unit 20 can providecorneal section images of differing time domains. Through processing bythe micro-processor 302, the high frequency vibrations (i.e. pressuredetection signal 60) generated by the cornea when the cornea is underintraocular pressure can be obtained. The micro-processor 302 thencompares the pressure detection signal 60 to the correspondingintraocular pressure and determines the intraocular pressure of the eye50. This principle is the same as utilizing the changes in capacitancegenerated by the high frequency vibrations of the cornea.

As shown in FIG. 10 of an intraocular pressure detecting method, themethod includes the following steps. Step 1010 involves capturing an eyeimage. Step 1020 involves analyzing the eye image and determining anintraocular pressure detection area. Step 1030 involves measuring anintraocular pressure of the intraocular pressure detection area togenerate a pressure detection signal. Step 1040 involves analyzing andcomparing the pressure detection signal. Step 1050 involves determiningthe intraocular pressure.

Although the preferred embodiments of the present invention have beendescribed herein, the above description is merely illustrative. Furthermodification of the invention herein disclosed will occur to thoseskilled in the respective arts and all such modifications are deemed tobe within the scope of the invention as defined by the appended claims.

1. An intraocular pressure detecting device, comprising: an imagecapturing unit for capturing an eye image; a processor unit electricallycoupled to the image capturing unit for determining an intraocularpressure detection area according to the eye image; a pressure detectionunit for detecting the intraocular pressure detection area andgenerating a pressure detection signal, wherein the processor unitdetermines an intraocular pressure according to the pressure detectionsignal.
 2. The intraocular pressure detecting device of claim 1, whereinthe image capturing unit comprises a photographic device, thephotographic device capturing the eye image.
 3. The intraocular pressuredetecting device of claim 2, wherein the eye image is selected from acornea image, an eyelid image, an eyebrow image, and an orbit image. 4.The intraocular pressure detecting device of claim 3, wherein the eyeimage comprises corneal thickness data, corneal section image data, andcorneal curvature data.
 5. The intraocular pressure detecting device ofclaim 1, wherein the processor unit comprises an analog-to-digitalconverter and a microprocessor, the analog-to-digital converterprocesses the eye image into an eye image signal, the micro-processoranalyzes the eye image signal and determines the intraocular pressuredetection area.
 6. The intraocular pressure detecting device of claim 1,wherein the pressure detection unit is an elastic member, the elasticmember comprises a first electrode and a second electrode, the firstelectrode and the second electrode form a capacitive sensing device. 7.The intraocular pressure detecting device of claim 6, wherein theelastic member further comprises a third electrode, the third electrodeis disposed between the first electrode and the second electrode toraise the signal-to-noise ratio.
 8. The intraocular pressure detectingdevice of claim 7, wherein the elastic member further comprises areference electrode, the reference electrode directly detects vibrationsof the intraocular pressure detection area.
 9. An intraocular pressuredetecting method, comprising: capturing an eye image; analyzing the eyeimage and determining an intraocular pressure detection area; measuringan intraocular pressure of the intraocular pressure detection area togenerate a pressure detection signal; analyzing and comparing thepressure detection signal; and determining the intraocular pressure.